Richard Matt, 48, and David Sweat, 34, cut through the walls in their cells, scaled a cat walk and escaped through a manhole cover a block away, in what Gov. Andrew Cuomo called an "elaborate plot" at a news conference held at the prison this afternoon.

There were a series of tunnels that led from the prison to the manhole, Cuomo said, adding that it's possible they followed heating pipes and the prison's inner workings to escape.

"You look at the precision of the operation," said Cuomo, who walked through their escape route, which started by drilling holes in their cells and ended with them climbing out of a manhole cover onto a public street. "It was truly extraordinary"

Officials are investigating how the two got their hands on the power tools.

The prison has accounted for its tools, but the tools could have come from an outside contractor, prison officials said. Numerous contractors work at the prison, Cuomo said.

"This is quite an unusual occurrence," Cuomo said. "We have more questions than we have answers."

Corrections officers perform night checks every two hours, but the two used hooded sweatshirts and other materials to create decoys to fool the guards, Cuomo said. The guards walk by, but do not wake up the inmates.

More than 200 law enforcement agents, including state, local and federal police, are searching for the two men. Three helicopters and K-9 units are also part of the search.

It's the first time an inmate has escaped from the maximum-security portion of the prison since it opened in 1865.

"First order of business is to find the two individuals and return them to prison," Cuomo said.

State police described Matt as a 6-foot-tall white male, weighing about 210 pounds. He has black hair and hazel eyes. He has a tattoo of a heart on his chest and left shoulder, a Marine Corps insignia on his right shoulder and a tattoo saying "Mexico Forever" on his back.

Sweat is 5-feet-11-inches tall and about 165 pounds. He has brown hair and green eyes. He has tattoos on his left bicep and on the fingers of his right hand.